268XA
Service Manual
5-14
channel 1 provides the full scale reading and measuring the four-wire short on
channels 2 and 12 determines the zero offset error. The four-wire ohms gain and
offset calibration constants are determined from these two measurements.
The 5700A provides a limited set of reference resistors where the best resistor for
each range is at 63.3% of full scale. This will give very good results, but making the
measurement closer to the full scale value using fixed resistors may give better
results. When you are using fixed resistors, you must use the CAL_REF command to
tell device the value of the new reference resistor. When you are using fixed resistors,
you connect the leads as they are for any four-wire ohms measurement.
4.
Resolve any calibration problems based on the following:
•
An execution error !> is returned by the CAL_STEP? command if the full scale
measurement is off by more than 5% from the target or if the zero measurement
is off by more than 1% of full scale. When an error is detected, the cal constant is
not updated, and the procedure remains at the same step.
•
When CAL_STEP? reports an execution error !> due to an out-of-range
measurement, it returns the raw measured reading to give you an indication of
what was measured. When CAL_STEP? completes successfully, it returns the
reference value.
•
If CAL_STEP? returns an execution error !> while measuring the four-wire short
on channels 2 and 12, the procedure freezes at the internal step that measures the
short. This way, you can send a CAL_REF? command and it will return 0 W,
indicating that the problem was probably caused by a misapplied short on
channels 2 and 12.
•
A device-dependent error is returned by the CAL_STEP? command if an internal
error such as a measurement timeout is detected. When an error is detected, the
cal constant is not updated, and the procedure remains at the same step.
•
An execution error !> is returned by the CAL_REF command if the specified
reference is less than 33% of full scale or greater than 100% of full scale for any
range.
Summary of Contents for 2680A
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Page 204: ...268XA Service Manual 7 10 268X FINAL ASSEMBLY alg105f eps Figure 7 1 268XA Final Assembly ...
Page 207: ...Replaceable Parts Parts Lists 7 7 13 2680A DIO alg100f eps Figure 7 3 DIO Module ...
Page 209: ...Replaceable Parts Parts Lists 7 7 15 2680A FAI alg102f eps Figure 7 4 FAI Module ...
Page 211: ...Replaceable Parts Parts Lists 7 7 17 2680A PAI alg103f eps Figure 7 5 PAI Module ...
Page 214: ...268XA Service Manual 8 2 ...
Page 215: ...8 3 8 Schematic Diagrams Figure 8 1 Backplane PCA 2680A 4001 ...
Page 216: ...268XA Service Manual 8 4 Figure 8 1 Backplane PCA cont 2680A 1001 ...
Page 217: ...8 5 8 Schematic Diagrams Figure 8 2 Controller System Power PCA 2680A 4004 ...
Page 223: ...8 11 8 Schematic Diagrams Figure 8 3 Digital I O PCA 2680A 4006 ...
Page 224: ...268XA Service Manual 8 12 Figure 8 3 Digital I O PCA cont 2680A 1006 1 of 3 ...
Page 225: ...8 13 8 Schematic Diagrams Figure 8 3 Digital I O PCA cont 2680A 1006 2 of 3 ...
Page 226: ...268XA Service Manual 8 14 Figure 8 3 Digital I O PCA cont 2680A 1006 3 of 3 ...
Page 227: ...8 15 8 Schematic Diagrams Figure 8 4 Backplane Extender PCA 2680A 4009 ...
Page 228: ...268XA Service Manual 8 16 Figure 8 4 Backplane Extender PCA cont 2680A 1009 ...
Page 229: ...8 17 8 Schematic Diagrams Figure 8 5 Extender PCA 2680A 4010 ...
Page 230: ...268XA Service Manual 8 18 Figure 8 5 Extender PCA cont 2680A 3010 ...
Page 231: ...8 19 8 Schematic Diagrams Figure 8 6 A D Supply Assembly 2680A 4031 ...
Page 232: ...268XA Service Manual 8 20 Figure 8 6 A D Supply Assembly cont 2680 1031 ...
Page 233: ...8 21 8 Schematic Diagrams Figure 8 7 PCMCIA PCA 2680A 4041 ...
Page 234: ...268XA Service Manual 8 22 Figure 8 7 PCMCIA PCA cont 2686 1041 ...
Page 235: ...8 23 8 Schematic Diagrams Figure 8 8 Output PCA 2680A 4062 ...
Page 236: ...268XA Service Manual 8 24 Figure 8 8 Output PCA cont 2680A 1062 ...
Page 237: ...8 25 8 Schematic Diagrams Figure 8 9 A D PFE PCA 2640A 4003 ...
Page 238: ...268XA Service Manual 8 26 Figure 8 9 A D PFE PCA cont 1 of 6 ...
Page 239: ...8 27 8 Schematic Diagrams Figure 8 9 A D PFE PCA cont 2 of 6 ...
Page 240: ...268XA Service Manual 8 28 Figure 8 9 A D PFE PCA cont 2640A 1003 3 of 6 ...
Page 241: ...8 29 8 Schematic Diagrams Figure 8 9 A D PFE PCA cont 2640A 1003 4 of 6 ...
Page 242: ...268XA Service Manual 8 30 Figure 8 9 A D PFE PCA cont 2640A 1003 5 of 6 ...
Page 243: ...8 31 8 Schematic Diagrams Figure 8 9 A D PFE PCA cont 2640A 1003 6 of 6 ...
Page 244: ...268XA Service Manual 8 32 Figure 8 10 A D FFE PCA 2645A 4003 ...
Page 245: ...8 33 8 Schematic Diagrams Figure 8 10 A D FFE PCA cont 2645A 1003 1 of 6 ...
Page 246: ...268XA Service Manual 8 34 Figure 8 10 A D FFE PCA cont 2645A 1003 2 of 6 ...
Page 247: ...8 35 8 Schematic Diagrams Figure 8 10 A D FFE PCA cont 2645A 1003 3 of 6 ...
Page 248: ...268XA Service Manual 8 36 Figure 8 10 A D FFE PCA cont 2645A 1003 4 of 6 ...
Page 249: ...8 37 8 Schematic Diagrams Figure 8 10 A D FFE PCA cont 2645A 1003 5 of 6 ...
Page 250: ...268XA Service Manual 8 38 Figure 8 10 A D FFE PCA cont 700p29_topress zip 2645A 1003 6 of 6 ...
Page 251: ...8 39 8 Schematic Diagrams Figure 8 11 Analog Input Connector PCA 2620A 4004A ...
Page 252: ...268XA Service Manual 8 40 2620A 1004 Figure 8 11 Analog Input Connector PCA cont ...
Page 253: ...8 41 8 Schematic Diagrams Figure 8 12 Display PCA 1 of 1 ...
Page 254: ...268XA Service Manual 8 42 Figure 8 12 Display PCA cont 1 of 1 ...